atmospheric chemistry

India: Why Was Daytime Ozone Pollution Higher During the Lockdowns?

The new PARLA laser in operation at ESO’s Paranal Observatory. The yellow-orange beam of the brilliant seven-watt laser is seen emerging from the dome of Unit Telescope 4 of the Very Large Telescope. In the background the Large Magellanic Cloud can also be seen. The laser creates an artificial star high in the atmosphere that can be used to correct images for the turbulence of the air and form much sharper pictures. Credit: European Southern Observatory, CC BY 4.0

How Could We Build an Invisibility Cloak to Hide Earth from an Alien Civilisation?